As a novice investor in the cryptocurrency market, I'm curious about how to purchase OriginTrail's Trac token. Could you please provide a step-by-step guide on the process? I'm particularly interested in knowing which exchange platforms support the trading of Trac, and what are the necessary prerequisites or requirements for purchasing the token? Additionally, I'd like to understand any potential risks or considerations I should be aware of before making my investment. Your insight and guidance would be greatly appreciated.